The Preclinical Tumor Analysis and Imaging (PTAI) Shared Resource is dedicated to facilitating in vivo studies of tumors by Cancer Center members. This Shared Resource serves to move research projects from the bench or from a patient's sample into an in vivo animal model context, thereby enhancing the translation of discoveries into useful knowledge for potential therapeutic applications. PTAI was formed by merging the pre-existing Molecular Assessment and Preclinical Studies (MAPS) shared resource with the Animal Imaging Shared Resource, so as to better integrate imaging into analyses of animal tumor models. The PTAI Shared Resource tests therapies involving small molecules, biologies, and/or radiation in a variety of tumor models and also helps translational investigators generate these models. This resource offers guidance and assistance for the design and performance of standardized or customized protocols for subcutaneous and orthotropic xenograft and syngenic mouse models. The PTAI Shared Resource uses ACUC approved protocols to perform preclinical studies, can follow established protocols, and will help investigators design custom protocols. New emphasis is placed on the noninvasive detection and measurement of tumor growth and spread using bioluminescence, PET or MRI. Staff members have considerable experience and serve as consultants and trainers as well as service providers. They also act as agents to coordinate services in other shared resources, providing a single point of contact for a PI to carry out an entire study that might include culture of cells, immunohistochemistry, flow cytometry, molecular analyses of tumors, and statistics. The PTAI provides laboratory services to clinicians, some of whom may not have appropriate laboratory facilities or staff, and initiates animal studies for laboratory scientists who have inadequate experience with in vivo models and otherwise depend solely on in vitro models. The advantages provided by in vivo preclinical studies include the development of whole animal model systems for 1) drug response predictions in human patients and analysis of mechanisms, 2) depicting the heterogeneity of human tumor cells, the complexity of which cannot be obtained within the confines of in vitro studies; 3) mimicking the tumor microenvironment and 4) tracking the progression, spread and invasion of metastatic cancers. The services offered by PTAI are an integral part of the Cancer Center translational research initiatives.